Method for external sterilization of drug delivery device

ABSTRACT

A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2) is provided, including placing the drug delivery device in a sterilization chamber, introducing into the chamber a dose of NO2 having a concentration of between about 2 and 20 milligrams per Liter by applying a vacuum level of between about 10 and 600 Torr and holding the vacuum level for a dwell time of between about 2 and 20 minutes, repeating the step of introducing into the chamber a dose of NO2 for a number of pulses between about 1 and 24, purging the sterilization chamber of at least substantially all of the NO2, and aerating the sterilization chamber.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Application No. 62/901,179, filed Sep. 16, 2019, U.S.

Application No. 62/905,341, filed Sep. 24, 2019, and U.S. Application No. 62/942,382, filed Dec. 2, 2019. The priority applications are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

This disclosure generally relates to an injection device for drug delivery for the injection device. More particularly, the disclosure generally relates to a method for externally sterilizing a drug delivery device.

BACKGROUND

As is known in the art, syringes are medical delivery devices used to administer a medicament to a patient. Syringes are often marketed either in prefilled form, wherein a set dosage of medicament is already provided therein, or they are empty and intended to be filled from a vial or other source of medicament by an end user at the time administration of the medicament is desired.

Syringes often include a barrel portion adapted to retain the medicament. The distal end of the barrel is often configured to include and/or mate with a conventional piercing element, such as a pointed needle cannula or a blunt ended cannula, to deliver the medicament contained in the barrel. The piercing element may be made of steel, plastic, or any other suitable material. A plunger rod may be inserted through the open proximal end of the syringe barrel and, through its engagement with an elastomeric or rubber-like stopper element fitted in a substantially fluid-tight manner within the interior of the barrel, a user can apply manual force to the plunger to deliver the medicament through the piercing element. A flange is also often provided around the open distal end of the syringe barrel as a form of finger rest to facilitate a user's manipulation of the device. In some examples, the syringe may also include backstop or component (a.k.a. “a backstop”) that is coupled with or connected to the flange to improve grip, usability, and or ergonomic design of the syringe. As a more specific example, the backstop may have a radial length that is greater than the length of the flange, thereby effectively extending the length of the grip surface. The backstop and/or the plunger rod may also or alternatively reduce or prevent inadvertent movement of the plunger rod and/or a stopper component. As a more specific example, backstop and/or the plunger rod may have component(s) that engage with each other to define a maximum point, in the retraction direction, that the plunger rod may be moved.

It may be desirable, both for integrity of the medicament as well as for patient safety, to sufficiently sterilize the components of the syringe. Sterilization may occur at several stages in the assembly process, including pre-fill stages (e.g., sterilization of the empty barrel and/or plunger) and post-fill stages (e.g., external sterilization of the assembled pre-filled syringe). External sterilization typically occurs after the pre-filled syringe has been filled, fully assembled, and located in at least some portion(s) of its final packaging. For some indications of use, such as certain ophthalmic indications, federal regulations may require external sterilization under certain conditions, parameters, and/or results.

External sterilization may pose design challenges. For example, medicament may be sensitive to sterilization and/or conditions thereof, such as temperatures, gases, radiation. Additionally, particularly in view of sensitivities of the medicament, it may be difficult to achieve a desired or required level of sterilization for the syringe and/or components thereof. As a more specific example, surface interactions between various components of the syringe and the backstop device and/or the syringe and the packaging may create or promote occluded spaces that may not be sterilized effectively and/or completely during external sterilization steps performed on the syringe. As a more specific example, surface interactions between the syringe and the backstop and/or the syringe and the packaging may create or promote occluded spaces. If occluded spaces prevent or resist an effective level of sterilant gas from reaching an area, then that are may not be effectively sterilized. If occluded spaces prevent or resist which prevent sterilant gas from being purged from an area, a patient could develop a superficial eye infection or a more serious condition such as endophthalmitis, such as patients that are already visually compromised before treatment. Therefore, it is desirable to maintain integrity of the medicament while reaching a suitable level of sterilization for all relevant portions and components of the syringe. Further, some sterilizing gases may be absorbed by many types of plastics and rubbers, which may negatively and/or undesirably impact the drug product inside and also subsequently negatively impact the efficacy, quality, and/or safety of the drug product. Other sterilizing gases may cause discoloration on the surface of the syringe, which may be undesirable for various reasons.

The present disclosure sets forth approaches embodying advantageous alternatives to existing external sterilization approaches, and that may address one or more of the challenges or needs mentioned herein, as well as provide other benefits and advantages.

SUMMARY

A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2) is provided, including placing the drug delivery device in a sterilization chamber, introducing into the chamber a dose of NO2 having a concentration of between about 2 and 20 milligrams per Liter by applying a vacuum level of between about 10 and 600 Torr and holding the vacuum level for a dwell time of between about 2 and 20 minutes, repeating the step of introducing into the chamber a dose of NO2 for a number of pulses between about 1 and 24, purging the sterilization chamber of at least substantially all of the NO2; and aerating the sterilization chamber.

The drug delivery device to be sterilized may be a pre-filled syringe comprising a barrel, a stopper, a plunger rod, and a backstop. The barrel of the pre-filled syringe may contain a medicament, such as a VEGF antagonist. The barrel may be a plastic barrel.

The vacuum level may be between about 100 and 500 Torr, between about 150 and 400 Torr, between about 150 and 300 Torr, or another suitable vacuum level.

The concentration of the dose of the NO2 may be between about 2 and 10 milligrams per Liter, between about 2 and 7 milligrams per Liter, or another suitable concentration of the dose.

The chamber may have a relative humidity of between about 70 and 90 percent or another suitable humidity.

The dwell time may be between about 2 and 12 minutes, between about 2 and 7 minutes, or another suitable dwell time.

The number of pulses may be between about 1 and 12, between about 1 and 8, between about 1 and 4, between about 1 and 2, or another suitable number of pulses.

The step of aerating the sterilization chamber may include aerating the sterilization chamber a number of cycles between about 12 and 70 or another suitable number of cycle to at least substantially prevent discoloration of the drug delivery device s.

The method of externally sterilizing the drug delivery device may achieve at least a 2 logs microbial reduction, may achieve at least a 3 logs microbial reduction, may achieve at least a 4 logs microbial reduction, may achieve at least a 5 logs microbial reduction, may achieve at least a 6 logs microbial reduction, or may achieve another suitable microbial reduction.

BRIEF DESCRIPTION OF THE DRAWINGS

It is believed that the disclosure will be more fully understood from the following description taken in conjunction with the accompanying drawings. Some of the drawings may have been simplified by the omission of selected elements for the purpose of more clearly showing other elements. Such omissions of elements in some drawings are not necessarily indicative of the presence or absence of particular elements in any of the exemplary embodiments, except as may be explicitly delineated in the corresponding written description. Also, none of the drawings is necessarily to scale.

FIG. 1 is a perspective view of an exemplary injection device according to aspects of the present disclosure, and having a syringe, having a barrel (partially shown), a flange, a plunger, and a backstop;

FIG. 2A is a perspective view of another exemplary injection device according to aspects of the present disclosure, and having a barrel, a flange, and a backstop;

FIG. 2B is an exploded perspective view of the device shown in FIG. 2A according to various embodiments of the present disclosure;

FIG. 2C is a front view of the device shown in FIG. 2A, showing the barrel (partial view) and the backstop according to various embodiments of the present disclosure;

FIG. 2D is a bottom view of the backstop and the syringe shown in FIG. 2A according to various embodiments of the present disclosure;

FIG. 2E is a perspective view of the backstop shown in FIG. 2B according to various embodiments of the present disclosure;

FIG. 2F is a front view of the backstop shown in FIG. 2B according to various embodiments of the present disclosure;

FIG. 2G is a top view of the backstop shown in FIG. 2B according to various embodiments of the present disclosure;

FIG. 2H is a bottom view of the backstop shown in FIG. 2B according to various embodiments of the present disclosure;

FIG. 3A is a perspective top view of an exemplary packaging according to aspects of the present disclosure, and that may be used for securing and/or holding an injection device, such as during external sterilization of the injection device;

FIG. 3B is a perspective bottom view of the packaging shown in FIG. 10A;

FIG. 3C is a perspective top view of the packaging shown in FIG. 10 with an exemplary injection device; and

FIG. 4 is a perspective top view of another exemplary packaging according to aspects of the present disclosure, that may be used for securing and/or holding an injection device, such as during external sterilization of the injection device;

FIG. 5A is a top view of another exemplary packaging according to aspects of the present disclosure, with a top protective cover removed and which may be used for securing and/or holding an injection device, such as during external sterilization of the injection device;

FIG. 5B is a top view of the exemplary packaging shown in FIG. 12A, with the top protective cover in-place;

FIGS. 6A-6C show various perspective views of the syringe from FIG. 1, highlighting areas of the syringe that may be particularly susceptible to gas occlusion during and after an external sterilization process according to various embodiments of the present disclosure;

FIG. 7 is a flowchart of a method of assembling and externally sterilizing a drug delivery device according to various embodiments of the present disclosure;

FIG. 8 shows a graphical illustration of ingress measurements of sterilization gas for various sterilization parameters, at different points in time, according to various embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure generally relates to injection devices which can be safely and reliably activated by a user for administering a drug, or in the case where a patient is the user, self-administering a drug. More particularly, the disclosure generally relates to approaches for external sterilization of a drug delivery device, which, in some examples, includes a syringe and a backstop and/or packaging configured to receive and/or support the syringe. The injection device may be a syringe, such as a pre-filled syringe containing a medicament. Using the approaches and/or “recipes” described herein, as well as variations of the same, a user may be able to utilize a desired bioburden kill level while minimizing or avoiding undesirable effects on the medicament. It is appreciated that the term “about” as used herein means+/−10% to the smallest significant digit.

FIG. 1 is a perspective view of an injection device 10, such as a syringe 10 generally having a barrel 11 having a proximal open end 11 a, a distal end 11 b (FIGS. 2A, 2B, 5A and 5B), a cavity 13, a flange portion 12, a plunger rod 16, a stopper component 18 (FIGS. 5A and 5B), and a backstop 20.

Due to the engagement between backstops and syringes, in some examples, sterilization gas may fail to reach occluded or partially occluded spaces between respective backstop and syringes and thereby fail to fully or suitably sterilize those surfaces. Additionally, or alternatively, the sterilization gas may not be effectively purged from these occluded or partially occluded spaces, thereby exposing the drug to the sterilization gas beyond the specified sterilization step in the chamber. Either and/or both of these situations may be undesirable. As a more specific example, FIGS. 6A-6C include various views of a syringe barrel and flange, with surfaces of the same that may be particularly susceptible to occlusion being identified with numeral 11 c (a proximal section of the barrel 11) and numeral 12 c (a proximal section of the flange 12). For example, a flange upper surface 12 c and a barrel outer surface 11 c may be particularly susceptible to occlusion due to their respective engagements with backstops known in the art.

The syringe barrel distal end 11 b includes and/or supports a needle or other suitable component for completing a fluid path into the patient. For example, the syringe barrel distal end may include a Luer lock component 17 (FIGS. 2A and 2B) and/or a protective cap 19 (FIG. 5A) covering the same. Before use the protective cap 19 may be removed so the Luer lock component 17 may receive a needle. The syringe barrel proximal end 11 a (see FIG. 2A) may receive the plunger rod 16 for pushing the stopper component 18 in the distal direction 15 and ejecting the drug from the syringe 10. For example, the stopper component 18 may form a fluid-tight relationship with the cavity 13 while also able to travel in the distal direction 15 along the cavity 13 and urge the drug from the distal end of the syringe 10. The plunger rod 16 may include a plunger rod end 14 with a larger diameter than the body portion of the plunger rod 16 to limit the travel distance of the plunger rod 16 in the distal direction 15 and/or to make it easier for the user to depress the plunger rod 16. The plunger rod 16 may be a one-way component, such that the plunger rod is not fixedly connected to the stopper so that if the plunger rod 16 is moved in the proximal direction (opposite the distal direction 15) then the stopper 18 does not move with the plunger rod 16.

FIGS. 5A and 5B show the syringe 10 positioned within a packaging 9 such as a blister pack 9 (collectively the packaged syringe 8). The packaging 9 includes a base portion 9 a and a cover 9 b (FIG. 5B) such as a Tyvek cover 9 b that extends substantially or completely across the base portion 9 a and/or is sealed thereto. The Tivek cover 9 b may extend outside of the border of the base portion 9 a in at least one portion, such as one side, to make it easier to remove the Tyvek cover 9 b. Additionally or alternatively, the base portion 9 a may include a tab portion 9 c that is not sealed with the Tyvek cover 9 b to promote easy removal.

The syringe barrel 11 may be made of plastic, glass, or any suitable material. As a more specific example, the syringe barrel 11 may be made of a plastic material including at least one or more of the following materials: certain grades of polypropylene (homo-polymer and/or co-polymer polypropylene), cyclo-olefin copolymer, cyclo-olefin polymer, cyclic olefin copolymer (COC), cyclo olefin polymer (COP), or other suitable materials. As a more specific example, the syringe barrel may be made of cyclo olefin polymer (COP).

The backstop 20 may be coupled with or connected with the syringe 10 to improve grip, usability, and or ergonomic design of the syringe. The flange 12 may include a diameter larger than that of the syringe barrel 11 and may serve as a finger rest permitting the user to manipulate the syringe 10 during use. For example, the user may rest two or more of her/his fingers against the flange 12 while using her/his thumb to depress the plunger rod end 14. As a more specific example, the backstop 20 may be coupled with the flange portion 12 to effectively extend the flange portion and thereby extend the length of the grip surface. As an even more specific example, it may be desirable to for a user to have a larger effective grip surfaces to improve grip, usability, and or ergonomic design of the syringe, particularly for certain applications of the syringe such as ophthalmic indications. However, it may be undesirable to increase the size of the flange portion 12 due to space constraints during manufacturing and shipping, advantages of scale for using a standard syringe/flange configuration. Additionally, syringes are commonly used in autoinjectors, which have a profile that may not accommodate a syringe with an enlarged flange size. Therefore, it may be desirable to have an additional component, such as a backstop component, that is able to be attached to and/or coupled with the syringe at a point in the manufacturing process.

The backstop may be manufactured from any suitable material. For example, it may be molded out of polypropylene (“PP”) or acrylonitrile butadiene styrene (“ABS”). ABS may have the advantage of being stiffer than PP and other materials so that the backstop can become lighter. As a more specific example, if the backstop is made from PP it may have a minimum wall thickness of 1.5 mm thickness, whereas if it is made from ABS it may have a minimum wall thickness of 1 mm.

The backstop 20 may also be utilized to limit, restrict, reduce, or prevent inadvertent movement of the stopper component 18 with respect to the syringe 10. For example, the backstop 20 may fit over the flange 12 to reduce or prevent inadvertent movement of a plunger rod 16. For example, as shown in FIG. 1, the backstop 20 may have locking surface 34 that engages the plunger rod 16 and restricts or prevents relative motion between the two components in the distal direction 15. As a more specific example, the plunger rod 16 may have a lock ring 16 a that has a larger diameter than the rest of the plunger rod 16 but a smaller diameter than the cavity; and the backstop 20 locking surface 34 may have a smaller diameter than the lock ring 16 a so that the lock ring 16 a is unable to travel in the proximal direction past the backstop 20. This arrangement would act to limit the proximal direction movement of the plunger rod 16.

For the above-discussed reasons, and perhaps others, the user typically does not remove the backstop 20 before using the syringe 10.

It may be desirable and/or required by regulations to externally sterilize an injection device during the manufacturing and/or assembly process. Additionally, some applications for pre-filled syringes (such as certain ophthalmic applications) require external sterilization. For example, 21 CFR 200.50 indicates, “Ophthalmic preparations and dispensers should be sterile.” Furthermore, ANSI/AAMI ST67:2011/(R)2017 states, “Sterilization of health care products—Requirements and guidance for selecting a sterility assurance level (SAL) for products labeled ‘sterile” and Section 4.1.1—states: “Generally an SAL value of 10-6 has been used for terminal sterilization of health care products.” Furthermore, Annex A to the ST67 and EN556-1:2006 provide: “Sterilization of medical devices—Requirements for medical devices to be designated “STERILE”—Part 1: Requirements for terminally sterilized medical devices” . . . Section 4.1: “For a terminally-sterilized medical device to be designated “STERILE”, the theoretical probability of therebeing a viable micro-organism present on/in the device shall be equal to or less than 1×10-6.” Therefore, it may be desirable and/or required for a bioburden to be less than 1×10-6 (e.g., 1×10⁻⁶).

Therefore, the disclosed embodiments herein are particularly advantageous for these types of applications. The terms “external sterilization” and/or “externally sterilize” as used herein refer to the process of sterilizing an injection device after it has been assembled. For example, the injection device shown in the figures may be externally sterilized after the syringe 10 (with a drug in the cavity 13), plunger rod 16, backstop 20, and protective cap (not shown) have all been assembled. During the external sterilization process, the injection device is typically placed in a sterilization chamber and exposed to a sterilization gas, such as Ethylene Oxide (EtO), Nitrogen Dioxide (NO2), Vaporized Hydrogen Peroxide (VHP), Carbon Dioxide (CO2), chlorine dioxide, or any other suitable gas, for a predetermined length of time and other specified conditions (such as temperature and pressure). Then, after the sterilization cycle, the sterilization gas is purged from the chamber and the injection device remains in the chamber (which is substantially or completely free of sterilization gas) for another predetermined length of time and other specified conditions (such as temperature and pressure).

FIGS. 2A through 2H, show another exemplary backstop 120, which may be utilized with a syringe 10 as shown in FIGS. 2A through 2C. The backstop 120 may generally include a collar portion 130 that extends around at least a portion of the syringe 10, an outer grip portion 140 for handling and/or gripping by the user, at least one protrusion such as a ridge 150 that helps permit or promote airflow through a space between the backstop and the syringe, a cavity 160 for receiving at least a portion of the syringe flange 12, and an opening 170 that permits the plunger rod 16 to extend through the backstop 120.

The collar portion 130, as best shown in FIGS. 2D through 2H, defines an inner surface 132 that extends around at least a portion of the syringe 10. As a more specific example, the inner surface 132 is a generally annular surface that extends around a substantial portion of a circumference of the barrel 11 of the syringe 10. As an even more specific example, the inner surface 132 extends around a substantial portion of a circumference of the distal portion 11 c of the barrel 11, the portion highlighted in FIGS. 13A-13C. The inner surface 132 may have generally the same curvature as the barrel 11 and may extend around the barrel 11 for the length of the inner surface 132. As shown in FIG. 2D, the inner surface 132 may extend around the inner surface of the collar 130 in a generally circular/annular manner except where the collar 130 and inner surface 132 are interrupted across an opening 134 in the collar 130 that permits the backstop 120 to be coupled with the syringe 10. As a more specific example, the opening 134 permits the backstop 120 to receive the syringe 10 by sliding the syringe 10 towards the backstop 120 (or vice versa) until the syringe 10 contacts the backstop 120 in a snap-fit configuration. As another example, the inner surface 132 extends for approximately 270 degrees around the circumference of the barrel 11. The axial length of the collar 130 (measured along the axis of the barrel 11) is approximately 5 millimeters, but may have other suitable lengths. As the axial length of the collar 130 is increased, the connection between the syringe 10 and the backstop 120 may become more secure. Also or alternatively, as the axial length of the collar 130 is increased, the center of gravity may move farther away from the axial length midpoint, thereby making it easier to orient the backstop 120 during manufacturing. As a more specific example, it may be desirable to assemble the syringes via automation and to utilize a “shaker” or a “feeder” receptacle such as a pan or a bowl to cause a plurality of backstop components in a shaking tray to become similarly oriented to streamline the manufacturing process. The feeder bowl may, for example, have a central receptacle with a spiral-path track along the sidewall of the receptacle that carries parts around the sidewall and up towards the top rim of the receptacle, where the parts can be fed to the assembly station. Often, a feeder bowl is more reliable and/or effective when the center of gravity of the components is at least a certain distance away from the axial length midpoint of the component, thereby causing all or substantially of the components to tip over towards the “heavy side” of the component. The center of gravity of the backstop 120 is designated by numeral 136 in FIG. 2F. Additionally, a feeder is often more reliable if the parts have some asymmetric features (at least along one or two of the axes) so the feeder has a track edge or pattern that can urge improperly oriented parts back into the bowl. In this case, the track edge or pattern feature serves as a gate; if the parts are in the right orientation then they will not interact with the feature but if they are in the wrong orientation then they will interact with the feature and fall back into the bowl.

As discussed above, the backstop 120 provides the user with a larger effective gripping surface than the flange 12 of the syringe 10. As a more specific example, the flange portion 12 shown in FIGS. 2A and 2B has a generally oval or oblong shaped configuration with a maximum width 12 a of approximately 13 millimeters and a barrel 11 diameter of approximately 9.5 millimeters. Therefore, the flange portion 12 has an effective grip surface of approximately 2 millimeters on each side of the flange portion 12. In comparison, the backstop 120 has a maximum width 120 a of approximately 34 millimeters and a collar width 130 b (FIGS. 2D and 2H) of approximately 12 millimeters. Therefore, the outer grip portion 140 of the backstop 120 has an effective grip surface of approximately 11 millimeters on each side of the collar 130.

The outer grip portion 140 has an angle 142 (FIG. 2C) of approximately negative 25 degrees with respect to the top surface 144 of the backstop 120. Therefore, the outer grip portion 140 has an angle of 115 degrees with respect to the syringe axis 11 d. It may be desirable for the angle of the outer grip portion 140 with respect to the syringe axis 11 d to be closer to 90 degrees than 180 degrees (i.e., 135 degrees or less) to allow the user to have a sufficient grip on the outer grip portion 140. It may be more desirable to have a smaller angle of the outer grip portion 140 with respect to the syringe axis 11 d, such as 125 degrees or less, or 120 degrees or less, or 115 degrees or less. The outer grip portion 140 may also include a non-slip or grip-enhancement feature such as ribs or a material with a relatively high coefficient of friction.

As discussed above, the backstop 120 may also include at least one protrusion such as at least one ridge 150 that engages the syringe 10 such that the collar inner surface 132 is spaced apart from the syringe 10. As a more specific example, the backstop inner surface 132 may include at least one protrusion 150 extending away from the inner surface 132 and configured to engage the flange 12 and/or the barrel 11 to permit or promote airflow through a space 152 between the inner surface 132 and the syringe 10. In FIGS. 2A through 2H, the backstop includes five ridges 150 a, 150 b, 150 c, 150 d, and 150 e that are generally spaced apart from each other around the collar inner surface 132 and are more preferably generally equally spaced from each other so as to form a five-point engagement between the backstop 120 and the syringe 10. However, any suitable of ridges may be used, such as one, or two, or three, or four, or five, or six, or seven, or eight, or nine, or ten, or more. The ridges 150 may be integrally formed in the backstop 120 collar inner surface 132 or they may be separate components attached to the collar inner surface 132. In either case, the ridges 150 may cooperate to permit a relatively secure fit between the backstop 120 and the syringe 10 while creating the space 152 between the inner surface 132 and the syringe 10. For example, the ridges 150 may engage the barrel 11 in a snap-fit relationship. The ridges 150 a, 150 b, 150 c, 150 d, and 150 e shown in the figures are generally parallel with the syringe axis 11 d, but they may have an alternative configuration. The ridges 150 a, 150 b, 150 c, 150 d, and 150 e shown in the figures may extend along the entire height 138 of the collar 130, as shown in FIG. 2E, or they may extend along only a portion of the height of the collar 130.

By permitting airflow through the space 152 (FIG. 2D) between the inner surface 132 and the syringe 10, the backstop 120 and the syringe 10 will cooperate to minimize or eliminate any occluded areas between the collar inner surface 132 and the barrel or the flange. For example, in one embodiment the ridges 150 are the only portions of the collar inner surface 132 that engage the barrel 11.

The protrusions on the backstop 120 shown in FIGS. 2A through 2H may instead have any suitable configuration that permits airflow the space 152 between the inner surface 132 and the syringe 10. For example, in one embodiment the protrusions may be replaced generally circular nodules, nubs, or other non-linear protrusion. As a more specific example, the protrusions on the backstop 120 may be positioned on the collar 130 instead of within the cavity.

As introduced above, the backstop 120 includes the cavity 160 for receiving at least a portion of the syringe flange 12. As a more specific example, the cavity is defined by opposing surfaces 162, 164 (FIGS. 2E and 2F). As shown in FIG. 2C, the distance between the opposing surfaces 162, 164 may be larger than the axial height of the flange 12 such that a gap 166 exists between at least one of the opposing surfaces 162, 164 and the top and bottom surfaces of the flange 12. As a more specific example, the gap 166 shown in FIG. 2C is between the lower opposing surface 162 and the bottom surface of the flange 12, but in other configurations a similar gap may exist between the upper opposing surface 164 and the top surface of the flange or may exist on both sides (top and bottom) of the flange 12. The gap 166 and other similar gaps described herein may be advantageous for permitting or promoting airflow and/or preventing or reducing occluded space.

The cavity 160 is preferably shaped and sized to receive the entire flange 12 to promote a secure engagement between the collar 130 and the barrel 11. Also, the cavity 160 may be shaped and sized to receive the flange 12 in any orientation to simplify and/or improve manufacturing. For example, the cavity 160 may be shaped and sized to receive the flange 12 with its maximum width in any orientation. As a more specific example, the minimum width of the cavity 160 may be at least slightly larger than the maximum width of the flange 12 such that the flange can be inserted in any orientation and/or the flange 12 can freely rotate within the backstop 120.

As introduced above, the opening 170 permits the plunger rod 16 to extend through the backstop 120. The opening 170 may be sized to permit free movement of the plunger rod 16 except when the lock ring 16 a abuts or engages the surface defining the opening 170. As a more specific example, the opening 170 may have a diameter or width that is at least slightly larger than the diameter or width of the portion of the plunger rod designated with numeral 16 in FIG. 1 (i.e., the section of the plunger rod with the plus-shaped cross-section) but the diameter or width of the opening 170 is at least slightly smaller than the diameter or width of the lock ring 16 a, thereby preventing or restricting the plunger rod 16 from moving in the proximal direction past the point shown in FIG. 1.

With reference to FIG. 7, an exemplary method of assembling and externally sterilizing a drug delivery device according to an embodiment of the present disclosure is provided. During a first step, in box 2, at least some individual components of a drug delivery device are sterilized, often prior to receipt by the manufacturing facility. For example, the syringe barrel and plunger stopper, and any other components that may have direct contact with the drug product, may be sterilized during this step. This step may utilize a variety of known techniques for sterilizing various unassembled components of the drug delivery device, including but not limited to components shown in FIGS. 1-6C. During a second step, in box 3, the barrel is filled and the stopper (a.k.a. the “plunger stopper”) is assembled with the barrel. The assembly step may also include adding at least some of the following: a plunger rod, a flange extender, a tip cap with Luer Lock, a needle, a rigid needle shield, and/or a backstop such as those shown in FIGS. 1-6C. At least some of these components may be pre-assembled with each other, but they may also be assembled at the filling line, such as if the filling process is performed aseptically. Also, the syringe typically will either have a tip cap Luer Lock tip or a mounted (e.g., staked) needle rather than having both components. Next, the external sterilization steps, designated by dotted line box 1, proceed.

In box 4, the syringes are preconditioned. For a process utilizing Nitrogen Dioxide (NO2), preconditioning may include at least some or all of the following steps: removing the samples from storage, allowing the syringes to adjust to room condition equilibration for a desired amount of time (such as 30 minutes, 90 minutes, 2 hours, or any desirable amount of time), and placing the syringes into a sterilization chamber. Preconditioning may occur inside or outside of the chamber.

When utilizing Ethylene Oxide (EtO), the precondition step may vary slightly than the step described for NO2. For example, the syringes may be preconditioned inside of the sterilization chamber (without gas injection) for 360 minutes (or another desirable length of time). However, as with the process utilizing NO2, the preconditioning step utilizing EtO may occur inside or outside of the chamber.

Next, for box 5, the sterilization chamber is closed and all or substantially all of the air is evacuated from the chamber. Next, in box 6, the sterilization chamber is humidified to a desired setting, such as 75 or 80 (or any desired amount of percentage of relative humidity).

Next, in box 7, the desired sterilization gas is injected and held in the chamber for a desired dwell time. For recipes utilizing NO2, the gas injection step 7 may include some or all of the following steps: delivering a dose of NO2 by pulling a vacuum in the chamber for a desired amount of time (i.e., dwell time) while injecting a desired amount of gas (dose concentration), purging the gas and release the vacuum, and then repeating these steps for a desired number of pulses. Once the number of desired pulses are complete, the gas is then finally purged (at box 8) so that the gas is removed from the sterilization chamber. Finally, in box 9, the chamber is aerated for a desired number of cycles (a.k.a. “Aeration Exchanges”) to ensure that all or substantially of the sterilization gas has been flushed from the syringe and packaging. In some examples, the vacuum level may vary during these steps; for example the vacuum during dwell time may be minimal, such as approximately 590 Torr.

The method may include any suitable parameters for steps 7-9, such as:

-   -   The vacuum level may be between about 100 and 500 Torr, between         about 150 and 400 Torr, between about 150 and 300 Torr, or         another suitable vacuum level.     -   The concentration of the dose of the NO2 may be between about 2         and 20 milligrams per Liter, between about 2 and 10 milligrams         per Liter, between about 2 and 7 milligrams per Liter, or         another suitable concentration of the dose.     -   The chamber may have a relative humidity of between about 70 and         90 percent or another suitable humidity.     -   The dwell time may be between about 2 and 20 minutes, between         about 2 and 12 minutes, between about 2 and 7 minutes, or         another suitable dwell time.     -   The number of pulses may be between about 1 and 24, between         about 1 and 12, between about 1 and 8, between about 1 and 4,         between about 1 and 2, or another suitable number of pulses.     -   The step of aerating the sterilization chamber may include         aerating the sterilization chamber a number of cycles between         about 12 and 35 or another suitable number of cycles.

As a more specific example, Table 1 shows different variables for ten different exemplary recipes for sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2):

TABLE 1 NO2 Relative Dwell Number Number Vacuum Dose Humidity Time of of (Torr) (mg/L) (%) (mins.) Pulses Aerations 20 10 75 10 8 28 20 20 80 20 4 24 20 10 80 20 4 24 20 10 80 10 4 24 20 10 80 10 2 24 20 10 80 10 1 24 20 5 80 10 1 24 20 5 80 10 2 24 20 5 80 5 2 24 500 5 80 5 2 70

As another example, Table 2 shows different variables for six different exemplary recipes for sterilizing a drug delivery device utilizing NO2:

TABLE 2 NO2 Relative Dwell Number Number Vacuum Dose Humidity Time of of (Torr) (mg/L) (%) (mins.) Pulses Aerations 20 10 75 10 8 12 20 10 75 10 12 12 20 10 75 10 24 12 100 10 75 10 8 12 100 10 75 10 12 12 100 10 75 10 24 12

In Tables 1 and 2, the “Vacuum Level (Torr)” column label refers to the vacuum force applied on the external sterilization chamber during step 4 in FIG. 1. As shown, the vacuum force varies from 20 Torr to 500 Torr, although different vacuum forces may be appropriate. The vacuum force numbers listed are inverse to their strength, such that a 20 Torr force is stronger than a 100 Torr force, which is stronger than a 500 Torr force (ambient pressure is typically about 760 Torr). The stronger the vacuum force, the greater the chance of demonstrating kill of the target bioburden. However, if the vacuum force becomes too high, then the process may result in undesirable effects on the medicament, such as causing the plunger to move undesirably (i.e. to move past the sterility barrier and cause a sterility breach). The “NO2 Dose (mg/L)” column refers to the concentration (in mg) of NO2 per liter of air introduced to the external sterilization chamber during step 7 in FIG. 7. As shown, the dose in Tables 1 and 2 varies between 5 and 20 mg/L, although different doses may be appropriate. The higher the dose of NO2 during this step, the faster and more completely the drug delivery device will be sterilized. However, if the dose of sterilization gas becomes too high, then the process may result in undesirable effects on the medicament, such as contaminating the inside of the drug barrel with sterilization gas (i.e., ingress of sterilization gas and/or discoloration of the syringe components). The “Relative Humidity (% RH)” column refers to the relative humidity in the external sterilization chamber during step 7 in FIG. 7. As shown, the relative humidity for each row in Tables 1 and 2 varies between 75% and 80%, although different relative humidity values may be appropriate. Increasing the relative humidity also increases the likelihood of demonstrating kill of the target bioburden. The “Dwell Time (mm:ss)” column refers to the amount of time that the drug delivery device sits in the sterilization chamber while sterilization gas is present. For Tables 1 and 2, the “Total Dwell Time” is equal to the “Dwell Time” column times the “Number of Pulses” column. For example, for the first row of Table 1, the samples would experience a Total Dwell Time of 80 minutes. As shown, the dwell times listed in Tables 1 and 2 vary between 5 and 20 minutes, although different dwell times may be appropriate. The dwell time also increases the likelihood of demonstrating kill of the target bioburden. However, if the dwell time becomes too high, then the process may result in undesirable effects on the medicament, such as contaminating the inside of the drug barrel with sterilization gas. The “Number of Pulses” column refers to the number of times during the NO2 process that the gas is injected by pulling a vacuum. As shown, the pulses for each row in Tables 1 and 2 varies from 1 to 24, although different values may be appropriate. The higher the number of pulses, the greater the chance of demonstrating kill of the target bioburden. However, if the number of pulses becomes too high, then the process may result in undesirable effects on the medicament, such as contaminating the inside of the drug barrel with sterilization gas. The column referring to “Number of Aerations” refers to the number of times that the chamber is aerated (box 9 in FIG. 7) after the gas is purged from the chamber (box 8 in FIG. 7). The exemplary process may utilize aeration exchanges of 12, 24, 28, 70, or any desirable number. Up to a certain point, by increasing the number of aerations, the manufacturer may increase the likelihood that all or substantially all of the sterilization gas is removed from the syringe and packaging (post-purge).

For each of the recipes in Tables 1 and 2 (NO2), each of the steps contained within box 1 in FIG. 1 may be performed at room temperature (25 degrees Celsius), but other appropriate temperatures may be used. However, other temperatures may be used, such as between about 2 degrees Celsius to about 8 degrees Celsius, or any other desirable temperature that does not undesirably affect the medicament.

Table 3 shows different variables for 10 different exemplary recipes for sterilizing a drug delivery device utilizing NO2:

TABLE 3 NO2 Relative Dwell Number Number Vacuum Dose Humidity Time of of (Torr) (mg/L) (%) (mins.) Pulses Aerations 100 10 75 10 2 24 300 10 75 10 2 35 100 20 80 20 4 24 20 10 80 10 4 24 100 10 75 10 2 24 100 20 80 20 4 24 20 10 80 10 4 24 300 10 75 10 2 35 20 10 80 10 4 24 20 20 80 20 4 24

When utilizing Ethylene Oxide (EtO), the gas injection step (box 7) varies slightly. For example, the gas injection step 7 may include some or all of the following steps: delivering a dose of EtO by pulling a vacuum in the chamber for a desired amount of time (i.e., dwell time) while injecting a desired amount of gas (dose concentration), and then purging the gas. In other words, when utilizing EtO, it may be desirable to run only one pulse rather than the preferred multiple pulses discussed above for NO2. For steps 8 (gas purge) and 9 (aeration), the exemplary process utilizing EtO proceeds as described above with respect to NO2.

At least some of the backstops illustrated in the figures were tested in a lethality study. For example, pre-filled syringes were “spiked” with between 1×10{circumflex over ( )}6 and 6×10{circumflex over ( )}6 CFU (e.g., between 1,000,000 and 6,000,000 CFU) of Geobacillus stearothermophilus before sterilization cycles. As a more specific example, the backstop and barrel portions of the prefilled syringes were spiked with the 1-6×10{circumflex over ( )}6 CFU of Geobacillus stearothermophilus. As used herein, the term “CFU” refers to “Colony-Forming Unit”, which is a unit used to estimate the number of viable bacteria or fungal cells in a sample (where “viable” is the ability to multiply via binary fission under controlled conditions). Geobacillus stearothermophilus (previously Bacillus stearothermophilus) is a rod-shaped, gram-positive bacterium and a member of the division Firmicutes. The bacterium is a thermophile and is widely distributed in soil, hot springs, ocean sediment, and is a potential cause of spoilage in food products. The spiked pre-filled syringes were then sterilized using various sterilization parameters to measure the lethality of the sterilization process to evaluate the Sterility Assurance Level (SAL). The pre-filled syringes were spiked with biological indicators or direct inoculation, as is discussed in more detail below.

Notably, different backstop portions such as the backstop portions 20 disclosed herein were tested in the lethality study. Table 4 shows results of the lethality study evaluating the effects of NO2 based sterilization on various pre-filled syringes with the backstop portions 20:

TABLE 4 NO2 Relative Dwell Recipe Vacuum Dose Humidity Time Number of Number of Spiked Spiked Number (Torr) (mg/L) (%) (mins.) Pulses Aerations Backstop Barrel PFS Samples Utilizing Backstop 20 1 100 10 75 10 2 24 1/5 5/5 2 300 10 75 10 2 35 0/5 5/5 3 100 20 80 20 4 24 0/5 5/5 4 20 10 80 10 4 35 2/5 5/5 PFS Samples Utilizing Alternative Backstops 5 20 10 75 10 8 28 5/5 5/5 6 20 20 80 20 4 24 5/5 — 7 20 10 80 20 4 24 5/5 — 8 20 10 80 10 4 24 5/5 — 9 20 10 80 10 2 24 5/5 — 10 20 10 80 10 1 24 5/5 5/5 11 20 5 80 10 1 24 5/5 4/5 12 20 5 80 10 2 24 5/5 5/5 13 20 5 80 5 2 24 5/5 5/5 15 500 5 80 5 2 70 5/5 5/5

For each recipe number, five samples (or at least 5 test locations on one or more samples) were tested. Table 4 shows, in the “Spiked Backstop” and “Spiked” Barrel” columns, how many out of the 5 samples reached the target lethality for each recipe. For example, the target lethality for this test was a Sterility Assurance Level (SAL) of 10{circumflex over ( )}6. In other words, the target lethality for this test was 6 logs reduction in the number of bacteria present (before sterilization vs. after sterilization). As a more specific example, for Recipe Number 1, one of the five samples tested reached this target lethality for the backstop area (Col. “Spiked Backstop”, row corresponding with Recipe Number 1), but all five of the samples tested reached this target lethality for the barrel area (Col. “Spiked Barrel”, row corresponding with Recipe Number 1). It should be noted that the spiked backstop test results for Recipe Nos. 1-4 (utilizing the backstop 20 shown in FIGS. 2A-2H) were tested via direct inoculation whereas the spiked backstop test results for Recipe Nos. 5-14 (utilizing alternative backstop 120)) were tested via biological indicators. It also should be noted that “-” symbols indicate that no data is reported for those parameters/samples. The testing method variance aside, the samples tested utilizing backstops with protrusions achieved target lethality at a much higher rate than the samples utilizing the backstop without protrusions. As discussed above, the ridges minimize and/or prevent occluded spaces and instead permit the sterilization agent to completely or substantially reach various components of the pre-filled syringe, particularly the backstop and flange areas.

Different sterilization parameters were also tested with respect to an ingress study. As discussed above, although it is desirable to achieve a target lethality during external sterilization, it is also desirable to reduce, minimize, and/or substantially prevent ingress of the sterilization gas into the drug product chamber. However, the two goals (achieving lethality and minimizing ingress) may serve as competing or counteracting interests. For example, some sterilization parameters that may improve the likelihood of achieving a higher lethality rate may increase the likelihood of having a higher ingress of sterilization gas. Table 5 below and FIG. 8 show results of an ingress study evaluating the effects of different recipes for NO2 based sterilization on the drug product chamber.

TABLE 5 Process Parameters NO2 Rel. Dwell Test Vac. Dose Hum. Time No. of No. of NO2 Content in Product (PPM) No. (Torr) (mg/L) (%) (mins.) Pulses Aerat. Day 1 Day 14 Day 30 Control 1 300 10 75 10 4 35 0.157 — 0.182 — 2 300 10 75 10 8 35 0.167 — 0.404 — 3 20 10 75 10 8 24 0.343 0.350 0.417 0.350 4 20 10 75 10 16 24 0.387 0.358 0.450 0.384 5 20 10 75 10 24 24 0.342 0.431 0.403 0.336 6 100 10 75 10 8 24 0.346 0.345 0.360 0.344 7 100 10 75 10 16 24 0.351 0.404 0.391 0.348 8 100 10 75 10 24 24 0.375 0.370 0.394 0.355 9 300 10 75 10 8 35 0.369 0.398 0.344 0.362 10 300 10 75 10 16 35 0.366 0.430 0.408 0.362 11 300 10 75 10 24 35 0.378 0.804 1.132 0.368

The last four columns to the right (collectively labeled “NO2 Content in Product (PPM)”) refers to the content of NO2 that ingress into the drug product container, more specifically the content of NO2 that ingress into the drug container, more specifically the NO2 level measured as part per million nitrate in the liquid. The first three columns in this group, labeled, “Day 1”, “Day 14”, and “Day 30” refer to the ingress as measured at different times after the sterilization process. The last column in this group, labeled “Control”, refers to the base level of nitrates (NO3), which is a product of the NO2 and the samples (water for injection). When compared against the Day 1, etc. “exposed” samples, the control “non-exposed” samples provides a baseline differentiation between the exposed sample and the control. For example, for test no. 5, the ingress for day 1 is 0.342 and the control is 0.336, so the difference between an exposed and non-exposed sample may be 0.006 PPM. As another, potentially related parameter, the test method may have an error rate of +/−0.1 PPM.

Although it may be generally desirable to minimize or to substantially or completely prevent ingress, it may be desirable to avoid exceeding an ingress content of 3 PPM, 1 PPM, or another suitable limit. It may be desirable to utilize the “raw” Day 30 values, such as those listed in the column in Table 5 above, or it may be desirable to utilize the “corrected” Day 30 values that have been adjusted based on the Control values. As shown above in Table 5 and in FIG. 8, almost all of the ingress values are below the threshold of 1 PPM (the only exception is the day 30 measurement for Sample 11). As is also shown in the above Table 5 and in FIG. 8, varying the different vacuum forces, number of pulses, and number of aerations has varying effects on the ingress measurements. Utilizing these parameters and trends, one may be able to determine sterilization parameters that accomplish a target lethality while staying below a desired ingress level.

Nitrogen dioxide (NO2) offers many advantages as sterilization gas, but in some examples, the sterilization process may cause discoloration on the surface of the injection device and/or components thereof. For example, one or more of the following components may experience discoloration: the syringe, the syringe barrel, the backstop device, the stopper, the plunger rod, and/or the protective cap. As another example, the injection device packaging, such as a peel-off cover for a blister pack, may also experience discoloration. Discoloration is generally undesirable, for cosmetic and other reasons.

Material type may be relevant for reducing, mitigating, and/or preventing discoloration from external sterilization steps. For example, some plastic materials may resist and/or mask discoloration more effectively than other plastic materials. As a more specific example, polypropylene may offer reduced discoloration (e.g. reduced yellowing) when compared to other materials, such as polycarbonate. Even more specifically, certain polypropylene blends may be even more effective in resisting and/or masking discoloration than others. As another example, polyethylene is another material that may resist and/or mask discoloration more effectively than other materials. As yet another example, polyesters such as polyethylene terephthalate (PET) and polyethylene terephthalate glycol (PETG) may resist and/or mask discoloration more effectively than other materials. As another example, polystyrenes such as polystyrene (PS) or acrylonitrile styrene acrylate (ASA) may also resist and/or mask discoloration more effectively than other materials. Polystyrene may be resistant to oxidation reactions, including those that take place during interactions with NO2. Acrylonitrile butadiene styrene (ABS) may be suitable for certain components of the injection device and/or the packaging, as ABS is a styrene-based resin with a white color instead of a clear color, thereby potentially resisting and/or masking discoloration. The blister pack may be made from any suitable materials, such as Polyethylene Terephthalate Glycol (PETG).

Material color may also be relevant for reducing, mitigating, and/or preventing discoloration from external sterilization steps. For example, as discussed above with respect to ABS, some materials may naturally have a certain color, pigment, or tone that makes them more suitable for reducing, mitigating, and/or preventing discoloration. Additionally, or alternatively, the addition of color tint to the material used to form the injection device components and/or the packaging may resist discoloration and/or the impacts thereof. As a more specific example, blue or gray tones may be particularly suitable for this purpose. The blue or gray tones may be added, for example, from a mixture of titanium dioxide (to generally provide white pigments) and/or carbon black (to generally provide black pigments).

Additives and/or stabilizers may also be utilized for reducing, mitigating, and/or preventing discoloration from external sterilization steps. For example, increased levels of resin additives and stabilizers, including but not limited to antioxidants, may be beneficial for reducing the appearance of discoloration. As discussed above, at least some of the discoloration from NO2 sterilization may be related to oxidation process(es); minimizing or reducing the effects of oxidation may thereby reduce discoloration. Such additives are currently added to standard resins, but a custom resin with an increased amount of additive may be beneficial for reducing, mitigating, and/or preventing discoloration.

As yet another example, post sterilization steps may also be utilized for reducing, mitigating, and/or preventing discoloration from external sterilization steps. For example, aeration of NO2 gas may reducing the effects of discoloration. As a more specific example, immediate and/or aeration steps or other steps involving exposure to fresh air may reduce and/or mitigate the effects of discoloration. Aeration steps are discussed in more detail below.

As another example, differences in part thickness, surface finish, whether the polypropylene is homo- or co-polymer, average molecular weight, and relative fraction of the additives could be the parameters that affect the amount of discoloration experienced by the components or perceived by a user.

FIGS. 3A through 3C show packaging 200 for an injection device according to another embodiment of the present disclosure. The packaging 200 includes support walls 210 for receiving and supporting an injection device, such as a syringe 10 shown in FIGS. 2A-2H. The packaging 200 may be utilized during various steps in the life cycle of the injection device, including during at least one or more of the following steps: external sterilization, transport to the user, pre-use storage by the user, preparation of the injection device and the injection site for use, and post-injection storage. For example, at a manufacturing site a manufacturer may place an assembled pre-filled syringe (for example, a syringe barrel, a backstop, stopper, plunger rod, drug, and protective cap) into the packaging such that the assembled pre-filled syringe is supported by the packaging 200 in a snap-fit connection between the support walls 210 and the syringe barrel. The manufacturer may perform external sterilization steps on the assembled pre-filled syringe while the assembled pre-filled syringe is supported by the packaging 200. The manufacturer may also then add a protective coating (not shown) over the top wall 212 of the packaging to form an air-tight seal and to define a chamber 214 within the packaging 200 that protects the assembled pre-filled syringe from outside air and/or contaminants. The protective coating may be a transparent plastic layer coupled to the packaging 200 through any suitable means such as an adhesive and/or a heat-sealing step. During another step in the life cycle of the injection device, a user may peel away the protective coating to gain access to the pre-filled syringe.

The packaging 200 may include protrusions or spacers to limit surface area contact between the tray and the injection device, thereby reducing or preventing occluded spaces therebetween. For example, the packaging 200 may include protrusions 220 extending outward from the support walls 210 of the packaging 200 to create a gap between the injection device and the packaging 200, thereby minimizing or preventing occluded spaces between the same. Thereby, the protrusions or spacers permit an effective connection between the packaging and the injection device while allowing sterilization gas to flow in between the respective components during external sterilization steps. The protrusions or spacers may also improve aeration (reduced time and/or improved effectiveness) of the sterilization gas after the external sterilization step. The packaging 200 shown in FIGS. 3A through 3C includes two protrusions 220, but any suitable number may be utilized. Also, the protrusions 220 shown in FIGS. 3A through 3C have a generally pyramid shape but may have any suitable shape. As another example, the packaging 200 may not include a snap-fit arrangement with the syringe and may instead allow the syringe to rest therewithin to allow sterilization gas to flow in between the respective components during external sterilization steps. In such a design, the gaps between the support walls 210 would be larger than the diameter of the syringe to allow space between the support walls 210 and the syringe. Also, in such a design, the Tyvek cover would preferably prevent the syringe from moving out of the packaging.

The packaging 200 includes a center section 240 of the cavity (between two snap fit areas 110) that is wider than other known center sections. For example, the distance 244 shown in FIG. 3C is preferably at least 1.5 centimeters to allow space for the user to grip the syringe 10 when removing the same from the packaging 200. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 2.0 centimeters. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 2.5 centimeters. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 3.0 centimeters. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 4.0 centimeters. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 5.0 centimeters. Even more preferably, the distance 244 shown in FIG. 3C is preferably at least 6.0 centimeters.

FIG. 4 shows packaging 300 for an injection device according to another embodiment of the present disclosure. For example, the packaging 300 includes a raised wall section 360 positioned near the portion of the packaging 300 that receives the plunger rod that secures the injection device plunger rod and/or prevents unintended movement of the injection device plunger. For example, the packaging 300 shown in FIG. 4 includes support walls 310 similar to those shown in FIGS. 3A-3C for receiving and supporting the barrel of the syringe 10. However, the packaging 300 shown in FIG. 4 also includes a raised wall section 360 that has side walls 360 a for receiving and supporting the plunger rod 16 and another wall 360 c that extends generally perpendicular to the support walls 310 and the side walls 360 a such as to receive the plunger rod end 14 and to prevent and/or restrict distal movement of the plunger rod end 14 (and the entire plunger rod 16) until the syringe 10 has been removed from the packaging 300.

In some examples, sterilization may cause discoloration. For example, the peel-off paper backing portion, such as Tyvek, of the blister pack that has undergone NO2 treatment may have a yellowish tone compared to an unsterilized sample. It may be desirable to use a peel-off paper backing portion of the blister pack that has one or more of the above-described characteristics for reducing or mitigating discoloration, such as pigments, color, additives/stabilizers, or a coating added to resist or repel discoloration from NO2 treatment. For example, it may be desirable to use adhesives for the Tyvek that are resistant and/or that mask discoloration due to NO2 sterilization. As a more specific example, ethylene vinyl acetate (EVA) may be used. However, in other examples, it may be desirable to use hot melt, which is a material that is composed of waxes and resins and is less prone to discoloration.

Similarly, it may be desirable to use components with one or more of the above-described characteristics for reducing or mitigating discoloration, such as pigments, color, additives/stabilizers, or a coating added to resist or repel discoloration from NO2 treatment for the pre-filled syringe, syringe components, and/or packaging. In other examples, certain adhesives (e.g., Oliver 27 HT-6 adhesive) may produce desirable results under the NO2 external sterilization and may exhibit minimal noticeable signs of discoloration compared to alternatives.

As will be recognized, the devices and methods according to the present disclosure may have one or more advantages relative to conventional technology, any one or more of which may be present in a particular embodiment in accordance with the features of the present disclosure included in that embodiment. Other advantages not specifically listed herein may also be recognized as well.

Preferably, the pre-filled syringe does not include an internal coating. The syringe may also comprise a coating on the outer surface of the syringe which is in contact with the environment such as an oxygen barrier coating.

The syringe barrel may have a length of 45 to 85 mm, 60 to 65 mm, or another suitable length. The length of the syringe barrel is the length between the rear end to the outlet to which the needle is attached (but not including the needle, if present).

The syringe barrel may have an internal diameter of 4 to 6.5 mm. If the syringe has a nominal maximum fill volume of 1 ml, the internal diameter of the syringe barrel may be 5.5 to 6.5 mm. If the syringe has a nominal maximum fill volume of 0.5 ml, the internal diameter of the syringe barrel may be 4 to 5 mm.

The wall of the syringe barrel may have a thickness of at least 1 mm; about 1 to 3 mm; about 1.5 to 3 mm; or about 2.4 to 2.8 mm. Due to the thickness of the wall, the sterilizing gas is restricted or prevented from entering interior of the syringe, thereby minimizing or preventing contact with the liquid formulation contained within the prefilled syringe.

The above description describes various devices, assemblies, components, subsystems and methods for use related to a drug delivery device. The devices, assemblies, components, subsystems, methods or drug delivery devices can further comprise or be used with a drug including but not limited to those drugs identified below as well as their generic and biosimilar counterparts. The term drug, as used herein, can be used interchangeably with other similar terms and can be used to refer to any type of medicament or therapeutic material including traditional and non-traditional pharmaceuticals, nutraceuticals, supplements, biologics, biologically active agents and compositions, large molecules, biosimilars, bioequivalents, therapeutic antibodies, polypeptides, proteins, small molecules and generics. Non-therapeutic injectable materials are also encompassed. The drug may be in liquid form, a lyophilized form, or in a reconstituted from lyophilized form. The following example list of drugs should not be considered as all-inclusive or limiting.

The drug will be contained in a reservoir. In some instances, the reservoir is a pre-filled syringe. The pre-filled syringe may have a maximum fill volume, i.e. a volume which can be maximally taken up by the syringe, of 0.3 ml to 1.5 ml, preferably of 0.5 ml to 1.0 ml. The volume of the liquid composition filled into the syringe may be about 0.05 ml to 1.0 ml; about 0.1 ml to 0.5 ml; about 0.14 ml to 0.3 ml; or about 0.15 ml to 0.2 ml. Syringes are typically filled with a larger volume than the volume actually administered to the patient to take into account any dead space within the syringe and the needle and the loss due to the preparation of the syringe for injection. Therefore, the volume which is actually administered to the patient may be between 0.01 ml and 1 ml; between 0.02 and 0.5 ml; between 0.025 and 0.5 ml; between 0.03 ml and 0.05 ml; or 0.05 ml.

In some embodiments, the reservoir of the pre-filled syringe includes a VEGF antagonist. The term “VEGF antagonist” refers to a molecule which specifically interacts with VEGF and inhibits one or more of its biological activities, e.g. its mitogenic, angiogenic and/or vascular permeability activity. It is intended to include both anti-VEGF antibodies and antigen-binding fragments thereof and non-antibody VEGF antagonists. Non-antibody VEGF antagonists include aflibercept, pegaptanib and antibody mimetics. Preferably, the non-antibody VEGF antagonist is aflibercept. Aflibercept which is presently marketed under the name Eylea® and which is also known as VEGF-trap is a recombinant human soluble VEGF receptor fusion protein in which portions of human VEGF receptors 1 and 2 extracellular domains are fused to the Fc portion of human IgGI (Holash et al. (2002) Proc. Natl. Acad. Sci. USA 99(17): 11393-11398; WO 00/75319 A1).

In some embodiments, the reservoir of the drug delivery device may be filled with or the device can be used with colony stimulating factors, such as granulocyte colony-stimulating factor (G-CSF). Such G-CSF agents include but are not limited to Neulasta® (pegfilgrastim, pegylated filgastrim, pegylated G-CSF, pegylated hu-Met-G-CSF) and Neupogen® (filgrastim, G-CSF, hu-MetG-CSF). In other embodiments, the drug delivery device may contain or be used with an erythropoiesis stimulating agent (ESA), which may be in liquid or lyophilized form. An ESA is any molecule that stimulates erythropoiesis. In some embodiments, an ESA is an erythropoiesis stimulating protein. As used herein, “erythropoiesis stimulating protein” means any protein that directly or indirectly causes activation of the erythropoietin receptor, for example, by binding to and causing dimerization of the receptor. Erythropoiesis stimulating proteins include erythropoietin and variants, analogs, or derivatives thereof that bind to and activate erythropoietin receptor; antibodies that bind to erythropoietin receptor and activate the receptor; or peptides that bind to and activate erythropoietin receptor. Erythropoiesis stimulating proteins include, but are not limited to, Epogen® (epoetin alfa), Aranesp® (darbepoetin alfa), Dynepo® (epoetin delta), Mircera® (methyoxy polyethylene glycol-epoetin beta), Hematide®, MRK-2578, INS-22, Retacrit® (epoetin zeta), Neorecormon® (epoetin beta), Silapo® (epoetin zeta), Binocrit® (epoetin alfa), epoetin alfa Hexal, Abseamed® (epoetin alfa), Ratioepo® (epoetin theta), Eporatio® (epoetin theta), Biopoin® (epoetin theta), epoetin alfa, epoetin beta, epoetin iota, epoetin omega, epoetin delta, epoetin zeta, epoetin theta, and epoetin delta, pegylated erythropoietin, carbamylated erythropoietin, as well as the molecules or variants or analogs thereof.

Among particular illustrative proteins are the specific proteins set forth below, including fusions, fragments, analogs, variants or derivatives thereof: OPGL specific antibodies, peptibodies, related proteins, and the like (also referred to as RANKL specific antibodies, peptibodies and the like), including fully humanized and human OPGL specific antibodies, particularly fully humanized monoclonal antibodies; Myostatin binding proteins, peptibodies, related proteins, and the like, including myostatin specific peptibodies; IL-4 receptor specific antibodies, peptibodies, related proteins, and the like, particularly those that inhibit activities mediated by binding of IL-4 and/or IL-13 to the receptor; Interleukin 1-receptor 1 (“IL1-R1”) specific antibodies, peptibodies, related proteins, and the like; Ang2 specific antibodies, peptibodies, related proteins, and the like; NGF specific antibodies, peptibodies, related proteins, and the like; CD22 specific antibodies, peptibodies, related proteins, and the like, particularly human CD22 specific antibodies, such as but not limited to humanized and fully human antibodies, including but not limited to humanized and fully human monoclonal antibodies, particularly including but not limited to human CD22 specific IgG antibodies, such as, a dimer of a human-mouse monoclonal hLL2 gamma-chain disulfide linked to a human-mouse monoclonal hLL2 kappa-chain, for example, the human CD22 specific fully humanized antibody in Epratuzumab, CAS registry number 501423-23-0; IGF-1 receptor specific antibodies, peptibodies, and related proteins, and the like including but not limited to anti-IGF-1R antibodies; B-7 related protein 1 specific antibodies, peptibodies, related proteins and the like (“B7RP-1” and also referring to B7H2, ICOSL, B7h, and CD275), including but not limited to B7RP-specific fully human monoclonal IgG2 antibodies, including but not limited to fully human IgG2 monoclonal antibody that binds an epitope in the first immunoglobulin-like domain of B7RP-1, including but not limited to those that inhibit the interaction of B7RP-1 with its natural receptor, ICOS, on activated T cells; IL-15 specific antibodies, peptibodies, related proteins, and the like, such as, in particular, humanized monoclonal antibodies, including but not limited to HuMax IL-15 antibodies and related proteins, such as, for instance, 146B7; IFN gamma specific antibodies, peptibodies, related proteins and the like, including but not limited to human IFN gamma specific antibodies, and including but not limited to fully human anti-IFN gamma antibodies; TALL-1 specific antibodies, peptibodies, related proteins, and the like, and other TALL specific binding proteins; Parathyroid hormone (“PTH”) specific antibodies, peptibodies, related proteins, and the like; Thrombopoietin receptor (“TPO-R”) specific antibodies, peptibodies, related proteins, and the like; Hepatocyte growth factor (“HGF”) specific antibodies, peptibodies, related proteins, and the like, including those that target the HGF/SF:cMet axis (HGF/SF:c-Met), such as fully human monoclonal antibodies that neutralize hepatocyte growth factor/scatter (HGF/SF); TRAIL-R2 specific antibodies, peptibodies, related proteins and the like; Activin A specific antibodies, peptibodies, proteins, and the like; TGF-beta specific antibodies, peptibodies, related proteins, and the like; Amyloid-beta protein specific antibodies, peptibodies, related proteins, and the like; c-Kit specific antibodies, peptibodies, related proteins, and the like, including but not limited to proteins that bind c-Kit and/or other stem cell factor receptors; OX40L specific antibodies, peptibodies, related proteins, and the like, including but not limited to proteins that bind OX40L and/or other ligands of the OX40 receptor; Activase® (alteplase, tPA); Aranesp® (darbepoetin alfa); Epogen® (epoetin alfa, or erythropoietin); GLP-1, Avonex® (interferon beta-1a); Bexxar® (tositumomab, anti-CD22 monoclonal antibody); Betaseron® (interferon-beta); Campath® (alemtuzumab, anti-CD52 monoclonal antibody); Dynepo® (epoetin delta); Velcade® (bortezomib); MLN0002 (anti-α4β7 mAb); MLN1202 (anti-CCR2 chemokine receptor mAb); Enbrel® (etanercept, TNF-receptor/Fc fusion protein, TNF blocker); Eprex® (epoetin alfa); Erbitux® (cetuximab, anti-EGFR/HER1/c-ErbB-1); Genotropin® (somatropin, Human Growth Hormone); Herceptin® (trastuzumab, anti-HER2/neu (erbB2) receptor mAb); Humatrope® (somatropin, Human Growth Hormone); Humira® (adalimumab); Vectibix® (panitumumab), Xgeva® (denosumab), Prolia® (denosumab), Enbrel® (etanercept, TNF-receptor/Fc fusion protein, TNF blocker), Nplate® (romiplostim), rilotumumab, ganitumab, conatumumab, brodalumab, insulin in solution; Infergen® (interferon alfacon-1); Natrecor® (nesiritide; recombinant human B-type natriuretic peptide (hBNP); Kineret® (anakinra); Leukine® (sargamostim, rhuGM-CSF); LymphoCide® (epratuzumab, anti-CD22 mAb); Benlysta™ (lymphostat B, belimumab, anti-BlyS mAb); Metalyse® (tenecteplase, t-PA analog); Mircera® (methoxy polyethylene glycol-epoetin beta); Mylotarg® (gemtuzumab ozogamicin); Raptiva® (efalizumab); Cimzia® (certolizumab pegol, CDP 870); Soliris™ (eculizumab); pexelizumab (anti-C5 complement); Numax® (MEDI-524); Lucentis® (ranibizumab); Panorex® (17-1A, edrecolomab); Trabio® (lerdelimumab); TheraCim hR3 (nimotuzumab); Omnitarg (pertuzumab, 2C4); Osidem® (IDM-1); OvaRex® (B43.13); Nuvion® (visilizumab); cantuzumab mertansine (huC242-DM1); NeoRecormon® (epoetin beta); Neumega® (oprelvekin, human interleukin-11); Orthoclone OKT3® (muromonab-CD3, anti-CD3 monoclonal antibody); Procrit® (epoetin alfa); Remicade® (infliximab, anti-TNFα monoclonal antibody); Reopro® (abciximab, anti-GP Ilb/Ilia receptor monoclonal antibody); Actemra® (anti-IL6 Receptor mAb); Avastin® (bevacizumab), HuMax-CD4 (zanolimumab); Rituxan® (rituximab, anti-CD20 mAb); Tarceva® (erlotinib); Roferon-A®-(interferon alfa-2a); Simulect® (basiliximab); Prexige® (lumiracoxib); Synagis® (palivizumab); 146B7-CHO (anti-IL15 antibody, see U.S. Pat. No. 7,153,507); Tysabri® (natalizumab, anti-a4integrin mAb); Valortim® (MDX-1303, anti-B. anthracis protective antigen mAb); ABthrax™; Xolair® (omalizumab); ETI211 (anti-MRSA mAb); IL-1 trap (the Fc portion of human IgG1 and the extracellular domains of both IL-1 receptor components (the Type I receptor and receptor accessory protein)); VEGF trap (Ig domains of VEGFR1 fused to IgG1 Fc); Zenapax® (daclizumab); Zenapax® (daclizumab, anti-IL-2Rα mAb); Zevalin® (ibritumomab tiuxetan); Zetia® (ezetimibe); Orencia® (atacicept, TACI-Ig); anti-CD80 monoclonal antibody (galiximab); anti-CD23 mAb (lumiliximab); BR2-Fc (huBR3/huFc fusion protein, soluble BAFF antagonist); CNTO 148 (golimumab, anti-TNFα mAb); HGS-ETR1 (mapatumumab; human anti-TRAIL Receptor-1 mAb); HuMax-CD20 (ocrelizumab, anti-CD20 human mAb); HuMax-EGFR (zalutumumab); M200 (volociximab, anti-α5β1 integrin mAb); MDX-010 (ipilimumab, anti-CTLA-4 mAb and VEGFR-1 (IMC-18F1); anti-BR3 mAb; anti-C. difficile Toxin A and Toxin B C mAbs MDX-066 (CDA-1) and MDX-1388); anti-CD22 dsFv-PE38 conjugates (CAT-3888 and CAT-8015); anti-CD25 mAb (HuMax-TAC); anti-CD3 mAb (NI-0401); adecatumumab; anti-CD30 mAb (MDX-060); MDX-1333 (anti-IFNAR); anti-CD38 mAb (HuMax CD38); anti-CD40L mAb; anti-Cripto mAb; anti-CTGF Idiopathic Pulmonary Fibrosis Phase I Fibrogen (FG-3019); anti-CTLA4 mAb; anti-eotaxin1 mAb (CAT-213); anti-FGF8 mAb; anti-ganglioside GD2 mAb; anti-ganglioside GM2 mAb; anti-GDF-8 human mAb (MYO-029); anti-GM-CSF Receptor mAb (CAM-3001); anti-HepC mAb (HuMax HepC); anti-IFNα mAb (MEDI-545, MDX-1103); anti-IGF1R mAb; anti-IGF-1R mAb (HuMax-Inflam); anti-IL12 mAb (ABT-874); anti-IL12/1L23 mAb (CNTO 1275); anti-IL13 mAb (CAT-354); anti-IL2Ra mAb (HuMax-TAC); anti-IL5 Receptor mAb; anti-integrin receptors mAb (MDX-018, CNTO 95); anti-IP10 Ulcerative Colitis mAb (MDX-1100); BMS-66513; anti-Mannose Receptor/hCGβ mAb (MDX-1307); anti-mesothelin dsFv-PE38 conjugate (CAT-5001); anti-PD1mAb (MDX-1106 (ONO-4538)); anti-PDGFRa antibody (IMC-3G3); anti-TGFβ mAb (GC-1008); anti-TRAIL Receptor-2 human mAb (HGS-ETR2); anti-TWEAK mAb; anti-VEGFR/Flt-1 mAb; and anti-ZP3 mAb (HuMax-ZP3).

In some embodiments, the drug delivery device may contain or be used with a sclerostin antibody, such as but not limited to romosozumab, blosozumab, or BPS 804 (Novartis) and in other embodiments, a monoclonal antibody (IgG) that binds human Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9). Such PCSK9 specific antibodies include, but are not limited to, Repatha® (evolocumab) and Praluent® (alirocumab). In other embodiments, the drug delivery device may contain or be used with rilotumumab, bixalomer, trebananib, ganitumab, conatumumab, motesanib diphosphate, brodalumab, vidupiprant or panitumumab. In some embodiments, the reservoir of the drug delivery device may be filled with or the device can be used with IMLYGIC® (talimogene laherparepvec) or another oncolytic HSV for the treatment of melanoma or other cancers including but are not limited to OncoVEXGALV/CD; OrienX010; G207, 1716; NV1020; NV12023; NV1034; and NV1042. In some embodiments, the drug delivery device may contain or be used with endogenous tissue inhibitors of metalloproteinases (TIMPs) such as but not limited to TIMP-3. Antagonistic antibodies for human calcitonin gene-related peptide (CGRP) receptor such as but not limited to erenumab and bispecific antibody molecules that target the CGRP receptor and other headache targets may also be delivered with a drug delivery device of the present disclosure. Additionally, bispecific T cell engager (BITE®) antibodies such as but not limited to BLINCYTO® (blinatumomab) can be used in or with the drug delivery device of the present disclosure. In some embodiments, the drug delivery device may contain or be used with an APJ large molecule agonist such as but not limited to apelin or analogues thereof. In some embodiments, a therapeutically effective amount of an anti-thymic stromal lymphopoietin (TSLP) or TSLP receptor antibody is used in or with the drug delivery device of the present disclosure.

Although the drug delivery devices, assemblies, components, subsystems and methods have been described in terms of exemplary embodiments, they are not limited thereto. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the present disclosure. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent that would still fall within the scope of the claims defining the invention(s) disclosed herein.

Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention(s) disclosed herein, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept(s). 

1. A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2), comprising: placing the drug delivery device in a sterilization chamber; introducing into the chamber a dose of NO2 having a concentration of between about 2 and 20 milligrams per Liter by applying a vacuum level of between about 10 and 600 Torr and holding the vacuum level for a dwell time of between about 2 and 20 minutes; repeating the step of introducing into the chamber a dose of NO2 for a number of pulses between about 1 and 24; purging the sterilization chamber of at least substantially all of the NO2; and aerating the sterilization chamber.
 2. A method as in claim 1, wherein the drug delivery device is a pre-filled syringe comprising a barrel, a stopper, a plunger rod, and a backstop and wherein the barrel contains a medicament.
 3. A method as in claim 1, wherein the medicament is a VEGF antagonist.
 4. A method as in claim 1, wherein the barrel is a plastic barrel.
 5. A method as in claim 1, wherein the vacuum level is between about 100 and 500 Torr.
 6. A method as in claim 1, wherein the vacuum level is between about 150 and 400 Torr.
 7. A method as in claim 1, wherein the vacuum level is between about 150 and
 300. 8. A method as in claim 1, wherein the concentration of the dose of NO2 is between about 2 and 10 milligrams per Liter.
 9. A method as in claim 1, wherein the concentration of the dose of NO2 is between about 2 and 7 milligrams per Liter.
 10. A method as in claim 1, wherein the chamber has a relative humidity is between about 70 and 90 percent.
 11. A method as in claim 1, wherein the dwell time is between about 2 and 12 minutes.
 12. A method as in claim 1, wherein the dwell time is between about 2 and 7 minutes.
 13. A method as in claim 1, wherein the number of pulses is between about 1 and
 12. 14. A method as in claim 1, wherein the number of pulses is between about 1 and
 8. 15. A method as in claim 1, wherein the number of pulses is between about 1 and
 4. 16. A method as in claim 1, wherein the number of pulses is between about 1 and
 2. 17. A method as in claim 1, wherein the step of aerating the sterilization chamber includes aerating the sterilization chamber a number of cycles between about 12 and 70 cycles to at least substantially prevent discoloration of the drug delivery device.
 18. A method as in claim 1, wherein the method of externally sterilizing the drug delivery device achieves at least a 2 logs microbial reduction.
 19. A method as in claim 1, wherein the method of externally sterilizing the drug delivery device achieves at least a 3 logs microbial reduction.
 20. A method as in claim 1, wherein the method of externally sterilizing the drug delivery device achieves at least a 4 logs microbial reduction.
 21. A method as in claim 1, wherein the method of externally sterilizing the drug delivery device achieves at least a 5 logs microbial reduction.
 22. A method as in claim 1, wherein the method of externally sterilizing the drug delivery device achieves at least a 6 logs microbial reduction.
 23. A method of externally sterilizing a drug delivery device utilizing Nitrogen Dioxide (NO2), comprising: placing the drug delivery device in a sterilization chamber; introducing into the chamber a dose of NO2 having a concentration of between about 5 and 20 milligrams per Liter by applying a vacuum level of between about 150 and 500 Torr and holding the vacuum level for a dwell time of between about 5 and 10 minutes; repeating the step of introducing into the chamber a dose of NO2 for a number of pulses between about 1 and 8; purging the sterilization chamber of at least substantially all of the NO2; and aerating the sterilization chamber a number of cycles between about 20 and
 90. 24. A method of externally sterilizing a pre-filled syringe having a drug container and a medicament contained in the drug container, the method of externally sterilizing comprising the following steps: placing the drug delivery device in a sterilization chamber; introducing into the chamber a dose of Nitrogen Dioxide (NO2) having a predetermined concentration by applying a predetermined vacuum level and holding the vacuum level for a predetermined dwell time; repeating the step of introducing into the chamber a dose of NO2 for a predetermined number of pulses; purging the sterilization chamber of at least substantially all of the NO2; aerating the sterilization chamber a predetermined number of cycles; wherein the method of externally sterilizing the pre-filled syringe achieves at least a log 6 lethality target for the pre-filled syringe while realizing an ingress of NO2 gas into the drug container of less than 3.0 parts per million, as measured 30 days after externally sterilizing the pre-filled syringe. 